The Chinese softshell turtle, Pelodiscus sinensis, is a species of turtle that was first described by Arend Friedrich August Wiegmann in 1835 (asTrionyx sinensis). The species is also referred to as the Asiatic soft-shelled turtle. There is a subspecies japonicus which is sometimes erroneously listed as Pelodiscus japonica.
The Chinese softshell turtle can reach a carapace length of 1 ft (0.30 m). It has webbed feet for swimming. They are called "softshell" because their carapace lacks horny scutes (scales). The carapace is leathery and pliable, particularly at the sides. The central part of the carapace has a layer of solid bone beneath it, as in other turtles, but this is absent at the outer edges. The light and flexible shell of these turtles allows them to move more easily in open water, or in muddy lake bottoms.
The carapace of these turtles is olive in color and may have dark blotches. The plastron is orange-red, and may also have large dark blotches. The limbs and head are olive dorsally with the forelimbs lighter and the hind-limbs orange-red ventrally. There are dark flecks on the head and dark lines that radiate from the eyes. The throat is mottled and there may be small, dark bars on the lips. A pair of dark blotches is found in front of the tail as well as a black band on the posterior side of each thigh.
These turtles are predominantly carnivorous and the remains of fish, crustaceans, mollusks, insects, and seeds of marsh plants have been found in their stomachs. They forage at night.
With their long snout and tubelike nostrils, these turtles can "snorkel" in shallow water. When resting, they lie at the bottom, buried in sand or mud, lifting their head to breathe or snatch at prey. Their basking habit is not well developed.
Chinese softshell turtles often submerge their heads in water. This is because they carry a gene which produces a protein that allows them to secrete urea from their mouths. This adaptation helps them survive in brackish water by making it possible for them to excrete urea without drinking too much salty water. Rather than eliminating urea by urinating through their cloaca as most turtles do, which involves significant water loss, they simply rinse their mouths in the water.
These turtles reach sexual maturity sometime between 4 and 6 years of age. They mate at the surface or under water. A male will hold the female's carapace with its forelimbs and may bite at her head, neck, and limbs. Females may retain sperm for almost a year after copulation.
The females lay 8–30 eggs in a clutch and may lay from 2 to 5 clutches each year. The eggs are laid in a nest that is about 3–4 in (76–100 mm) across at the entrance. Eggs are spherical and average about 20 mm (0.79 in) in diameter. After an incubation period of about 60 days, which may be longer or shorter depending upon temperature, the eggs hatch. Average hatchling carapace length is about 1 in (25 mm) and width is also about 1 in (25 mm).
In the UKEdit
This species has been introduces to a handful of marshed around North Yorkshire. Probably only around 3-4 breeding pairs.